By 2015 the average size was down to 114sqm, with the average price rising to $970,789 or $8,493 per sqm.
Realestate.co.nz chief executive Brendon Skipper said the reduction reflected "the greater popularity of smaller townhouses, as well as infill housing coming on to the market".
In comparison, the price per sq m for the capital city fell by 2.6 per cent, to $3,294, while a Wellington home's average size was steady at 156sqm and the total average house price dipped from $526,722 to $512,258.
Of the 19 regions surveyed the cost per sqm has risen in 12. Auckland had the biggest increase but the Coromandel rose 35.13 per cent in the average price per sqm, to $8288. Wairarapa had the biggest drop in price, 7.7 per cent to $2301 per sqm.
House moves
Changing cost per square metre since 2013
• Auckland: Up by 75.94 per cent
• Wellington: Down by 2.6 per cent
• Canterbury: Up 3.6 per cent
• Southland: Up 12.29 per cent
Change in the size of our homes since 2013
• Auckland: 27.66 per cent smaller
• Wellington: Same size on average
• Canterbury: 3.57 per cent bigger
• Southland: 2.69 per cent smaller